1. Field of the Invention
The present invention relates to an image forming apparatus, particularly to an image forming apparatus including a USB (Universal Serial Bus) connector attachable to a USB device.
2. Description of the Related Art
Recently, with the widespread use of USB memories, it is frequently seen that a user always carries a USB memory in which document data is stored.
In order to comply with such a case, among MFPs (Multi Function Peripherals) which are one example of the image forming apparatus, an MFP with a so-called USB memory print function and a so-called USB memory scan (also referred to as a Scan To USB memory) function has been increasing in number. With the USB memory print function, documents stored in the USB memory are printed with the MFP. With the USB memory scan function, paper-medium data is digitized and stored in the USB memory attached to the USB connector.
In this respect, when the USB memory scan function is performed for a large amount of documents, the user possibly leaves the spot before the job is completed. When the USB memory scan function is performed, image data is converted to a PDF (Portable Document Format) or the like after the scan operation on the large amount of documents is completed, and a write operation to the USB memory is performed. Therefore, it may take a considerable time to perform the conversion of the large amount of documents to the image data and the write operation processing.
Also, the user who performed the USB memory print function possibly takes only the outputted paper media and the user leaves the MFP with the USB memory itself still attached to the MFP.
Accordingly, the user sometimes forgets to extract the USB memory although the job such as the USB memory scan function and the USB memory print function has been completed.
For example, Japanese Laid-Open Patent Publication No. 2006-140644 discloses a technique in which, in order to prevent the user from forgetting to extract the USB memory, the print operation is not started unless the USB memory is extracted.
However, in the case where the technique disclosed in Japanese Laid-Open Patent Publication No. 2006-140644 is used in the MFP, since the user usually thinks that the print operation will be started when a print button is pressed, the user possibly cannot see the MFP manipulation that the print operation is not started unless the USB memory is extracted.
On the other hand, the case in which the function is expanded by connecting an external device to the USB connector of the MFP is increased because of diversification of the USB device.
Examples of the expanded function include a USB keyboard, a USB-IC card reader, a USB finger-print authentication device, and a USB mouse. A plurality of USB connectors are generally mounted on the MFP for these expanded functions.
Generally, the MFP is produced for multi users, the job can be operated in a multi mode, and access to the USB device can also be operated in the multi mode. Accordingly, a plurality of USB memories are sometimes attached to the plurality of USB connectors of the MFP.
In this respect, when, in the MFP used in a multi mode environment by multi users, a plurality of USB devices share a connectable environment, there is a limitation in the number of connectors to which the USB devices can be connected, and there is a limitation in the number of connectors which can be used by the plurality of users.
For example, the access to the USB device for data storage, data write, and the like is stopped, and the use of the USB device is restricted until the connector becomes vacant even if the USB device is extracted without any problem.
Although the user who wants to use the USB device can extract the USB device whose job is actually completed, the user possibly mistakenly extracts the USB device in an access state when no connector connectable to the USB device (empty port) exists. In the case where the connector to which a USB device can be connected does not exist when a new USB device is to be connected and used, the user sometimes waits for the time when another person who possesses the USB device completes the use of the USB device to extract the USB device.
In a MFP which can reserve a plurality of jobs to perform the jobs in a predetermined order, a USB memory can be attached to reserve a job. However, in the case where a new job cannot be performed because connectors for USB memories are closed, the user cannot distinguish between the USB memory with which another person reserves a job and the USB memory in which another person does not reverse a job, e.g., a USB memory whose data is transferred to the MFP side. Therefore, the user hardly finds whether the USB memory can be extracted.
Furthermore, in the same situation, the user is not sure how long it takes for the user to be able to extract the previous USB device and insert a new USB device.
In the case where both the USB memory and a USB hard disk (HDD) are attached to a connector while other USB devices, e.g., a USB HDD in addition to the USB memory can be attached, the user may sometimes not sure which of the USB memory and the USB HDD can be preferentially extracted.
Thus, a plurality of connectors to which USB devices can be connected cannot efficiently and effectively be used in the conventional technique.